Liquid crystal display devices have recently been improved in the display quality and are now widely used for TVs, but are still strongly desired to be further improved in the display quality.
One problem unique to liquid crystal display devices is that the display quality varies in accordance with the angle at which the display is observed (viewing angle), namely, that the so-called viewing angle characteristic is lowered. In conventional TN mode liquid crystal display devices, the grayscale is occasionally inverted. The liquid crystal display devices which are widely used today can display images at a contrast ratio of 10 or greater in a relatively wide viewing angle range, but still have the problem that the grayscale characteristic (γ characteristic) is dependent on the viewing angle.
In order to solve this problem, the so-called pixel division technique is proposed. “Pixel division” refers to a method by which the luminance, that is conventionally displayed with one pixel, is displayed with 2 or more sub-pixels obtained by dividing one pixel in a space-wise or time-wise manner. The two or more sub-pixels include at least a bright sub-pixel displaying a luminance higher than the luminance to be displayed and a dark sub-pixel displaying a luminance lower than the luminance to be displayed. The technique of space-wise pixel division is described in, for example, Patent Documents 1 through 3. The technique of time-wise pixel division is described in, for example, Patent Document 4.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-62146    Patent Document 2: Japanese Laid-Open Patent Publication No. 2004-78157    Patent Document 3: Japanese Laid-Open Patent Publication No. 2005-189804    Patent Document 4: Japanese Laid-Open Patent Publication No. 2005-173573    Non-patent Document 1: Shinpen Shikisai Kagaku Handbook (Color Science Handbook, Revised) (2nd ed.), edited by the Color Science Association of Japan, published by University of Tokyo Press, pp. 1026-1027, 1303 (1998)